In general, an inclination sensor is used for a safety system of a vehicle, which detects a turnover of the vehicle and, for example, cuts off the feeding of oil and/or switches off the ignition power supply system.
There has been developed an inclination sensor which comprises a case attached to a vehicle body, a pendulum type movement capable of freely rotating in the case in accordance with inclination of the vehicle body and a detector capable of electromagnetically sensing the magnetized part of the movement when a turnover of vehicle occurs (JP 2000-146582 and JP 2001-256871).
The above-mentioned conventional inclination sensor still involves such a problem that the movement of the pendulum is not smooth from the friction of its shaft ends bounded in bearing units of the case. In addition, the movement is directly affected by the oscillation of a running vehicle body since the oscillation may be directly transmitted thereto through the shaft. When the case is tilted in the direction reverse to that of the movement, the movement is stopped by being pressed to a ribbed portion of the case, which is internally formed for restriction of the movement in the axial direction of the movement. Namely, there takes place a so-called “sticking” phenomenon of the movement.
The conventional inclination sensor uses a pendulum type movement having a notched upper part so as to possess its gravity center at the lower side. This causes the movement of the sensor to swing unstably and largely with the oscillation of the running vehicle, decreasing the response of the movement of the sensor.